# Forums

## What charging rates are people seeing with the model S?

Love my Model S! But, it charges slower than what Tesla has advertised.

On a standard wall socket, Tesla claims 5mi/hr of charge. I get 3.
On a NEMA 14-50 socket, drawing a full 40A, Tesla claims 31mi/hr of charge. I get 24.

Anything I might be doing wrong? What do others see?

Thanks!

Getting Amped Again | 01. Dezember 2012

@Mike6 - I think the ambient temperature during charging might be important so I suggest the respondents include that. Does the Model S include an external temperature gauge?

nickjhowe | 01. Dezember 2012

Is that rated or projected miles?

The math based on a Rod&Barbara post is 240V * 40A / 307wh/m = 31 rated miles per hour charging.

If you are pushing less than 240V, drawing less current, or showing projected rather than rated you'll get a different answer.

There was a post somewhere that said it can take a few weeks for the batteries to fully bed themselves in, and a recommendation to use the full range charge mode for the first few charges.

I don't have my car yet so all the above is based on info in the forum rather than personal experience.

Superliner | 01. Dezember 2012

The car can handle 85 - 265V @ my house the so called 240V Nema is actually closer to 215 - 220V so I'm anticipating similar results as yourself, and remember their estimates assume "ideal conditions" and optimal 120 / 240V supply voltages.

MarkV | 02. Dezember 2012

The on-screen projections are based on the EPA rating of 265 mile range with a full charge of 85 kWh. That is an average of 320 wh/mile. My charging circuit is the standard NEMA 14-50. I actually get 239.5 volts and the car will only draw 40 amps which is 9580 watts supply to the car. This equates to 9580/320 = 29.9 miles/hour. So I do not think there is anything to worry about if your particular charging rate is a lower figure unless, of course, you do not have time between drives to get fully recharged. Personally, I have been doing the "standard charge" and only drawing 30 amps. This only requires about 5 hours for my daily commute of about 100 miles. When my solar charging becomes active I may even reduce the charging rate further to reduce the stress on my solar battery bank.

robwarnersc | 02. Dezember 2012

A few questions for people that have already taken delivery of their "S" please....
1- What is the length of cable you get for charging car?
2- Is it possible to lengthen the cable for 220 charging?
3- I was told yesterday that constant 110 charging is "not good" for the batteries as it is never good to charge batteries slowly. Does anyone know more about this? Is anyone using 110 as their primary charging rate?
4- If you go on a roadtrip, even with super charging stations and you visit someone for a few days and their home (access to 110 only) is over 100 miles away from a super charging station, what would you suggest to top off battery to make it to a super charging station or how do you get access to 220 so you don't have to kill many hours of your time waiting at an RV park? I am trying to understand the "limitations" and "allowances" with the S, even with the 300 mile range.
Thank you.

cosmomusic | 02. Dezember 2012

I have two NEMA 14-50 socket installed. One at home and one at work, which is a commercial building. My charge rate at home is 28 mls/hour, and 24 mls/hour at work. The voltage being delivered to my car at home is 240, while at work its 230. The reason is, commercial buildings in CA only deliver max 230v - I was told by electrician. Thus, the charge rate is dependent on the energy being delivered to the car, and not a Model S problem.The car should display the amperage and voltage it is receiving while charging. If your system says 40A-240V and your are not getting around 28 ml/hour, then this could be a car problem. I doubt this is the case, however. Remember, Model S can take 300 miles/hour from the supercharger.

Brian H | 02. Dezember 2012

cosmomusic;
The SC is a DC feed, however; all other systems go through the car's own chargers (AC/DC converters/rectifiers). Don't know if they could be a problem.

David M. | 02. Dezember 2012

I would think the charging rate would vary somewhat based on state of charge. You know your cell phone will charge much quicker when it's at a 20% state of charge, than when it's at an 80% state of charge. Maybe the same with Model S? Has anyone done a comparison on a NEMA 14-50?

I don't know (or care) how long it takes to charge my cell phone, because I plug it in at bedtime, and when I wake up, it's at 100%. Same should be true of Model S, unless I'm on a roadtrip, where hopefully I can rely on SuperChargers and random hotel charging (or Random RV Park charging) across the street from my hotel.

Liz G | 02. Dezember 2012

@robwarnersc

From what I've heard it is advisable to charge at only the rate necessary to charge your battery in the time you have available before driving again (aka as slow as possible). With that in mind I'm not sure why charging on a 110 would cause issues. Though I defer to other with more electrical knowledge than me.

I did ask my 0EA about the charging rate on a 240 and if it would slow down as the battery got closer to being fully charged (similar to what happens with the Superchargers). I said he thought it would but because of the rate of charge it would not be as noticeable.

Would be interesting to see if anyone with an S could test that and report back to the group.

Mike6 | 02. Dezember 2012

Thanks everyone - this is helpful.

Not sure why mineis charging slowly.... :-(

mrspaghetti | 02. Dezember 2012

@mike6

What are the actual voltages on your outlets?

Brian H | 02. Dezember 2012

Mike;
What does TM Service have to say? Some have had problems/gliches with their chargers.

joe_slovensky2001 | 02. Dezember 2012

Requesting inio for new home construction. I have model s coming this Month and electrician want to what type of plug nema 14-50 is what I gather. But how large a breaker should I put in the box? Just 40 amp or can I go to 50,60 or 70? By increasing ampurae from main box to plug will I get faster charging?

Thx

pilotSteve | 03. Dezember 2012

My 6-50 outlet using the mobile connector is showing 40A @ 235-239V, and 10kW charge. Thats exactly what Tesla says to expect with that plug.

Charge starts lower but within 2 minutes is 10 kW, then tapers off to 9 kW and lower after about 230 miles of range has been charged.

Tonight I had 90 Ideal miles (started with 305 [range charge] this morning) and after a few mins of charging, when it showed 10kW (40A) it estimated 5± hours to full [standard] charge. Thats in the 30-35 mph charge rate.

Can't wait for my HPWC to see a full charge like only 4 hours. (@80 amps).

mrspaghetti | 03. Dezember 2012

@joe_slovensky20

I believe the ”50” in ”14-50” tells you what size breaker to use. Put in a bigger one and you may burn down your house.

scottssp | 03. Dezember 2012

The charging rate slows down when you get closer to full charge. Even on the Super Chargers, over 160 mile charge the rate goes down to 100 miles an hour and slows down from there. So if you want a full charge there you need about 1.5 to 2 hours to get it. Found out (The hard way, wife not happy with the extra wait) on my way to Vegas this weekend. Contacted Tesla about it, they stated they are working on getting the rate to stay up. Not the 160 per 1/2 as advertised.

mrspaghetti | 03. Dezember 2012

@scottssp

The 'advertised' capability of the supercharger is to get you at least a half-charged battery in 30 minutes. That is not the same as a constant rate of 150 miles/half hour of charge, i.e., you can't extrapolate that to assume a fully charged battery in 1 hour.

The way you're describing how the supercharger works, it looks like it's functioning exactly as designed - to charge your battery as quickly as possible without ruining it. Whoever told you they're working on 'getting the rate to stay up' is misinformed.

Chuck Lusin | 03. Dezember 2012

@ joe_slovensky20,

Your electrician should know these things already. For the Nema 14-50 you need a 50A breaker, and min 8 gauge copper wire. Long runs require a thicker wire, to prevent voltage drop and heat build up. You might consider a different electrician, if they don’t know the basics.

William9 | 03. Dezember 2012

scottssp - So I roll into Barstow showing 117 rated miles, needing 143 rated miles to get to a range charge of 260 miles. What is your estimate of the time to accomplish?

Selina | 28. Dezember 2012

We are in the process of building a home with the wall charger, but we are about 7 months away from finishing. Right now we are stuck with charging the model s with 110 in the parking garage of our condo. Painfully slow as we are getting a rate of 2 miles pr/hr charge. Unfortunately this will be our main charge point until our house is complete.

Has anyone had any luck increasing the amps in the charge mode to 15 on a 110? right now it always charges at 110 / 12. I was hoping to eek out 3 miles pr hour charge, any suggestions?

drp | 28. Dezember 2012

I see a Chargepoint stop on a route i can take through Michigan, with NEMA 5-20R. Does anyone know if we can use it and what e time/charge may be compared to J-1772!

July10Models | 28. Dezember 2012

@Selina
It depends on what the circuit breaker on that circuit is rated. You can't use 15A continuously on a 15A circuit because the breaker will trip. However if the circuit is a 20A circuit you should be able to go up to 18A continuously. You can also see if there is another outlet nearby that maybe coming from a differing phase. That would be ideal because you can create a 240 Volts outlet pigtail and charge at twice the rate (240V and 13A). If the nearby outlet is the same phase you can still use it to bump up your current draw to the max of 15A or 20A depending on the rating of the CB but, not recommended! Consult with an electrician who can look at your specific cituation.

July10Models | 28. Dezember 2012

Situation

ReeceWeb | 28. Dezember 2012

@Selina

I have successfully charged at 16A from a 20A 120V outlet. To do this, I had to work around the 12A limit the car enforces when you are using the NEMA 5-15 tip.

I made an adapter with a NEMA 5-20 plug and a 14-50 receptacle. I then used the 14-50 charging tip and manually set the charging current to 16A. (You have to set the current limit BEFORE you plug in). This arrangement seems to work fine even though the charger is only receiving 120V from a tip that would usually receive 240V.

If you know for sure the branch is rated for 20A and it doesn't share with any other loads, then you could do the same. Look at my posts on this thread for more details.

jat | 28. Dezember 2012

@Selina - when running a continuous load (over 3 hours), you have to derate the breaker and wire by 25% because heat builds up. That is why you get 12A on a 15A circuit (15/1.25). @July10ModelS is right except that you also have to worry about the wire to the outlet and the outlet itself -- there is a reason it is a 15A outlet. You can get 20A outlets (NEMA 5-20, the left slot has a sideways slot as well), but you have to be sure that the wire to it is rated for it and you would then need a 20A adapter plug for the mobile connector.

Another option would be if this is a dedicated line from the breaker, you could run 240V over it (swap out the breaker and send L1/L2/ground over the 3-conductor wire rather than L1/neutral/ground; the Model S doesn't need neutral), and you could get 12A or 16A (depending on the wire) at 240V, which would double your charge rate (you would need to make a custom adapter to go from NEMA 6-20 to an 6-50 or 14-50, and then program the car to only draw the right amount of current. Don't do this if you can't be sure there is nothing else on that branch circuit (or disconnect it if it is).

@joe_slovensky - the breaker can't be larger than what the wiring and the plug will accept. If you want to charge higher than 40A, you need to run heavier wire and then you will need the HPWC instead of a regular outlet. In my case, I had 100A wire run with a temporary 14-50 receptacle on it until I get the HPWC.

Back to the original topic, here is a post where a Model S owner shows a graph of the charge rate:

Brian H | 28. Dezember 2012

Selena;
Can you occasionally (say, weely) get a full charge at a commercial or other outlet? Then you'd be less limited by the little you eke[note sp.] out from the 110.

I also wonder if you have a 240V supply at the construction site you can use for a few hours now and then.

Brian H | 28. Dezember 2012

typo: weekly

rwang | 29. Dezember 2012

Talked to a few Tesla engineers. They think they can do the whole charge in 1 hour soon. it's in the software algorithm. That should help.

dstiavnicky | 30. Dezember 2012

One hour full charge? Wow!
Makes you wish you lived across the street from a Supercharging station...